#define _CRT_SECURE_NO_WARNINGS
#include <stdio.h>
#include<assert.h>

char* my_strcat(char* dest,const char* src)
{
	assert(dest && src);
	char* ret = dest;
	while (*dest)
		dest++;
	while (*dest++ = *src++)
		;
	return ret;
}


int main()
{
	char arr1[20] = "I can ";
	char arr2[10] = "do it!";
	printf("%s \n", my_strcat(arr1, arr2));
	return 0;
}